A kind of auxiliary identification method of sweetpotato drought-resistance need be established to drought screening of new materials and breeding drought-resistance new varieties，promote sweetpotato planting in dry barren hills，inland arid etc. marginal land，reduce the workload of field identification. On the basis of identification of sweetpotato drought-resistance in the field, PEG-6000 simulate water stress, the relation of drought-resistance and physiological changes under was discussed. The results show that: Through drought identification in the field, Guangshu87 and Xushu22 have strong drought-resistance, Rizi0602 and Ningzishu1 have poor drought-resistance. Under stress, with the increasing of PEG concentration , the activity of NOS, CAT, T-AOC and T-SOD of sweetpotato leaves increased gradually, the content of Pro, MDA, Prot and T-AA also increased; especially after 24 h sweetpotato leaves were treated in 25% PEG-6000, drought resistance index and the relative values of NOS,T-AOC,Pro of sweetpotato leaves showed a significant positive correlation，the relative value of RWC and drought resistance index showed a highly significant positive correlation，drought resistance index and D value of NOS,T-AOC, Pro, RWC showed a significant positive correlation（r=0.8944）.so the D value of this four physiological indexes could be used for preliminary identification of sweetpotato drought-resistance.